A Digital Watermarking Algorithm In Wavelet Domain

With the development and popularity of computer and the communication technology, the transportation and trade of multimedia information is becoming so convenient that it has reached to an unprecedented width and depth, however, the consequent piracy has appeared and been getting severe. How to make fully use of the convenience the internet brings to us and at the same time protect the property right effectively has turned out to be an internationally important issue. The digital watermarking emerges as the time requires, it has been a hot point of the information security as a significant tool to protect the multimedia digital products.Digital watermark performs by embedding unseen marks into digital data. Although the embedded marks are generally unseen or unobservable, the can be detected or extracted. The watermarks are tightly integrated to and hidden in the original data (they can be image, audio, video data) so as to become an unseparated part of original data and survive some operations which do not do harm to the data's value when used and in the business.This paper considers the static digital image as the main research object. It firstly summarizes the background of digital watermarking development and the basic theory framework, and then introduces a digital watermarking algorithm in the wavelet domain and its application and analyzes which kind of image and watermark suit this algorithm. The main work includes:A digital watermarking algorithm based on discrete wavelet transformation (DWT) and singular value decomposition (SVD) is proposed. It makes well use of the characteristics of DWT and SVD by doing singular value decomposition to the subbands of muli-DWT of the Arnold jumbled watermark and embedding those singular value data to the corresponding multi-DWT subbands of the original image. Emulational experiments are did in Matlab and the experimental results indicates that the proposed algorithm is invisible, robust and secure. It has been proved by the experiment to be fit for protecting the property right of static gray image by embedding meaningful binary watermark.